This invention relates to an auxiliary hoisting apparatus, particularly for a building structure, such as a cooling tower having a casing which is not self-supporting and which is secured to a cable net framing supported by a mast. When the construction of a cooling tower of the above-outlined type has reached the stage where the mast is in place and at least the principal portion of the cable net is tensioned between a head ring mounted on the mast and the foundation members, the completion of the cable net framing and the attachment of the casing require a very substantial amount of work. This is particularly the case when the casing is formed of a great number of plates which are adjoiningly attached to the cable net framing.